import java.util.Scanner;

public class Demo2 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        //在此输入您的代码...
        int a = scan.nextInt();
        int b = scan.nextInt();
        int c = scan.nextInt();
        if (a > b + c) {
            System.out.println('l');
        } else if (b > a + c) {
            System.out.println('q');
        } else if (c > a + b) {
            System.out.println('b');
        } else {
            System.out.println(-1);
        }
        scan.close();
    }
}
